The study of cell behavior is important in many fields including biology, medicine and pharmacology. Since cell-functions include many interrelated pathways, cycles and chemical reactions and since there is a large variation of cell biochemistry amongst similar cells, the study of a bulk of cells, whether the bulk is homogenous or heterogeneous, does not usually provide sufficiently detailed or interpretable results: rather a comprehensive study of cell biological activity is often advantageously performed by examining single isolated living cells as individuals. The use of single-cell assays is an important tool for understanding biological systems and the influence thereupon of various stimuli such as exposure to active entities.
In order to understand cell behavior, for example, such as the response to stimuli such as various biological modulators, two fundamental research capabilities are often desirable (i) the ability to track temporal behavior of large groups of cells as individuals for periods of minutes, hours and even days and (ii) the ability to identify and study cell heterogenity, a phenomenon existing even in synchronized cell lines.